Daniel Penny trial resumes as fellow Marine vet explains chokehold training on witness stand

A Marine veteran who served alongside New York City subway chokehold suspect Daniel Penny took the stand Thursday during his trial on manslaughter charges in the death of Jordan Neely.

Joseph Caballer, a former Marine sergeant, said he had given Penny martial arts instruction and explained a "blood choke" designed to knock out an aggressor in just a few seconds with pressure to the carotid artery - which he said is never held more than 5 seconds in training. That's different from an "air choke," which applies pressure to the aggressor's Adam's apple and can be held for minutes.

Prosecutors showed a picture of the subway chokehold and Caballer said it looked like an attempted figure-four blood choke. However, Caballer said Penny's arm "could be" putting pressure on Neely's trachea instead. 

"Is there any point Mr. Penny appears to be applying a blood choke fully for Mr. Neely to go unconscious?" Raiser asked while showing images from eyewitness video.

"Not from what I can see," Caballer replied. 

When asked if there's any reason why the hold should be released completely before Penny was 100% convinced that Neely was no longer a threat, Caballer said the decision would be up to Penny's judgment.

"If you release the hold too soon, there could be struggling, fighting," he said.

After the video played again, Caballer said that at the start, Penny did not appear to be applying as much pressure as he was at the 1 minute, 43 second mark, when Neely started struggling, and then he relaxed his grip again.

Under redirect examination from the prosecution, Caballer backed off of an earlier exchange in which he suggested Penny could have been holding a botched blood choke. 

"Based off just the assumption that he was applying pressure, yeah it could have been some kind of air choke," he said, adding that the Marines don't teach air chokes.

"The training we teach can be modified based on the situation that they're facing," he said later.

"He told like everyone that he had like a rough day, and that he don't care what happens today, he don't care about going to jail, but that someone's dying today," the witness said.

Another witness complained to responding officers about their delayed response: "Everybody, I was calling 911, they took mad long to come. He was trying to resist him while somebody came, but they took mad long."

"Dude got up and saw he was about to hurt somebody, and he got up and he restrained him," that witness added, referring to Penny. "And he was trying to restrain him until the police came."

Going into the sixth day of testimony, prosecutors already called 31 people to the stand.

Thursday's proceedings were expected to include testimony from the city medical examiner's office, the lead detective on the case and a Marine sergeant who trained Penny. The jury was also expected to see video from Penny's initial interrogation.

On Tuesday, a man who appeared on video helping Penny hold Neely down testified. 

Eric Gonzales told the court that at one point he said Penny wasn't holding Neely tight enough, that he felt a pulse when they both finally let go, that he had been granted immunity from prosecution in exchange for testifying - and that he initially lied to investigators. 

Fox News' CB Cotton contributed to this report.